The present invention relates to compounds that are useful as catalyst components. More particularly the present invention relates to such compounds that are particularly adapted for use in the coordination polymerization of unsaturated compounds comprising an anion containing at least two Lewis basic sites which are coordinated to Lewis acids. Such compounds are particularly advantageous for use in a polymerization process wherein catalyst, catalyst activator, and at least one polymerizable monomer are combined under polymerization conditions to form a polymeric product.
It is previously known in the art to activate Ziegler-Natta polymerization catalysts, particularly such catalysts comprising Group 3-10 metal complexes containing delocalized xcfx80-bonded ligand groups, by the use of Bronsted acid salts capable of transferring a proton to form a cationic derivative or other catalytically active derivative of such Group 3-10 metal complex. Preferred Bronsted acid salts are such compounds containing a cation/ anion pair that is capable of rendering the Group 3-10 metal complex catalytically active. Suitable activators comprise fluorinated arylborate anions, such as tetrakis(pentafluorophenyl)borate. Additional suitable anions include sterically shielded diboron anions of the formula: 
wherein:
S is hydrogen, alkyl, fluoroalkyl, aryl, or fluoroaryl, ArF is fluoroaryl, and X1 is either hydrogen or halide, disclosed in U.S. Pat. No. 5,447,895. Additional examples include carborane compounds such as are disclosed and claimed in U.S. Pat. No. 5,407,884.
Examples of preferred charge separated (cation/ anion pair) activators are ammonium, sulfonium, or phosphonium salts capable of transferring a hydrogen ion, disclosed in U.S. Pat. Nos. 5,198,401, 5,132,380, 5,470,927 and 5,153,157, as well as oxidizing salts such as ferrocenium, silver or lead salts, disclosed in U.S. Pat. Nos. 5,189,192 and 5,321,106 and strongly Lewis acidic salts such as carbonium or silylium salts, disclosed in U.S. Pat. Nos. 5,350,723 and 5,625,087.
Further suitable activators for the above metal complexes include strong Lewis acids including tris(perfluorophenyl)borane and tris(perfluorobiphenyl)borane. The former composition has been previously disclosed for the above stated end use in EP-A-520,732, whereas the latter composition is similarly disclosed by Marks, et al., in J. Am. Chem. Soc., 118, 12451-12452 (1996). For the teachings contained therein, the foregoing patents, publications and equivalent United States applications are hereby incorporated by reference.
Despite the satisfactory performance of the foregoing catalyst activators under a variety of polymerization conditions, there is still a need for improved cocatalysts for use in the activation of various metal complexes under a variety of reaction conditions. Accordingly, it would be desirable if there were provided compounds that could. be employed in solution, slurry, gas phase or high pressure polymerizations and under homogeneous or heterogeneous process conditions having improved activation properties.
According to the present invention there are now provided compounds useful as catalyst activators corresponding to the formula: (A*+a)b(Z*J*j)xe2x88x92cd,
wherein:
A* is a cation of charge +a,
Z* is an anion group of from 1 to 50, preferably 1 to 30 atoms, not counting hydrogen atoms, further containing two or more Lewis base sites;
J* independently each occurrence is a Lewis acid coordinated to at least one Lewis base site of Z*, and optionally two or more such J* groups may be joined together in a moiety having multiple Lewis acidic functionality,
j is a number from 2 to 12 and
a, b, c, and d are integers from 1 to 3, with the proviso that axc3x97b is equal to cxc3x97d.
Additionally according to the present invention there is provided a catalyst composition for polymerization of an ethylenically unsaturated, polymerizable monomer comprising, in combination, the above described compound and a Group 3-10 metal complex that is capable of activation to form an addition polymerization catalyst, or the reaction product of such combination.
Additionally according to the present invention there is provided a process for polymerization of one or more ethylenically unsaturated, polymerizable monomers comprising contacting the same, optionally in the presence of an inert aliphatic, alicyclic or aromatic hydrocarbon, with the above catalyst composition.
The foregoing compounds are uniquely adapted for use in activation of a variety of metal complexes, especially Group 4 metal complexes, under standard and atypical olefin polymerization conditions. Because of this fact, the foregoing compounds are capable of forming highly desirable olefin polymers in high efficiency.